Various communication systems are used to enable inmates of prisons and other institutions to talk with loved ones, friends, attorneys, and others who are outside of the institution. Unfortunately, inmates and these outside parties are not always able to connect due to availability, timing, and call restrictions. For example, an inmate may try to call home to the inmate's mom during calling hours set by the institution and happen to call when the mom has stepped out, has a visitor, or is otherwise not available. Similarly, an inmate may be unable to contact an attorney if the attorney is on another call, in court, or otherwise unavailable. In addition, inmate calls are often restricted so that only calls initiated by the inmate are permitted. The inmate's family and contacts outside of the institution are often thus required to wait for a call from inmate, which is burdensome and often results in calls occurring at inconvenient times and places.
Inmate calling systems generally charge inmates (or the called parties) for the calls between the inmate and called parties. The rates charged for these calls are generally used to, among other things, pay carrier charges to reach the called parties over conventional telephone lines. In addition, use of these carrier-based systems can impose various restrictions. For example, carrier network limitations in existing systems limit interface compatibility with Dual Tone Multi-Frequency (DTMF) signals and impose restrictions that result in undesirable routing of calls. In many instances, least cost routing techniques are employed that frustrate the use of DTMF signals. Such least cost routing techniques will route calls over the least expensive carrier regardless of whether that carrier uses switches in all Point Of Presences (POPs) that can understand DTMF signals coming from a called party, e.g., when a party presses “3” to accept a call, etc. As a result, many calls that involve DTMF signals cannot be completed without manually changing from the least cost carrier to another carrier for the individual phone number. This is inefficient, frustrating for customers, and burdensome of the providers. Thus, although many inmate calling systems use Voice Over Internet Protocol (VOIP) for communications within the institution and from the institution to monitoring and control systems, the communications generally interface with conventional phone lines and cellular phones, incur calling carrier charges, and often must manually work around burdensome restrictions.